1. Field of the Invention:
The present invention relates generally to improved trailers and lifting mechanisms having improved reliability and safety features. More specifically, the invention relates to an improved lifting mechanisms for use with gooseneck trailers.
2. Background Information:
Gooseneck trailers commonly are employed in conjunction with heavy-duty pickup trucks to transport livestock and other cargos. Such gooseneck trailers are provided with wheels at the rearward end and a connecting arm extending from a mid-region of the forward end of the trailer. The connecting arm includes a gooseneck portion with a ball receptacle to connect with a ball protruding upwardly from the truck bed. The ball and ball receptacle provide a means of connecting the trailer to the truck.
Because gooseneck trailers have wheels only at their rearward end, the trailer must be provided with some means of supporting the front end of the trailer when the trailer is coupled or uncoupled from the truck. Conventionally, a manually operated jack stand is provided at the front of the trailer to perform this function. Such manually operated jack stands typically are provided with a manual crank arrangement and locking pin that is manually operated to extend and retract the jack relative to the trailer and to lock the jack in an extended or retracted position. This manually operated jack requires excessive physical effort to move the manual crank, which is in a dangerous location. It is sometimes necessary to lift the trailer when loaded with cattle or other heavy cargo, which increases the required physical effort and risk to the operator.
U.S. Pat. No. 5,125,679, Jun. 30, 1992 to Delano discloses such a jack stand that is mounted to the trailer to rotate in and out of a vertical position. Such manual jacks expose the operator to risk and require substantial physical strength for operation, particularly when a trailer is loaded with upward of 20,000 pounds of cargo. Also, manual operation requires the operator be in close proximity to the rear of the truck and under at least a portion of the trailer to operate the jack stand during coupling and uncoupling operations. Such manual operation can be very dangerous to the operator.
A number of prior-art references disclose lifts or leveling apparatuses for use with towed vehicles. U.S. Pat. No. 4,928,488, May 29, 1990, to Hunger discloses an hydraulic support device for semi-trailers. Hunger's lift employs three separate pumps to accomplish extension, retraction, and load raising functions. Such a support device is overly complicated and is not easily adapted for use with a gooseneck trailer, in which the hydraulic cylinders are subject to damage from the rear bumper of the towing vehicle. U.S. Pat. No. 4,235,542, Nov. 25, 1980, to Paterik, Jr. discloses a self-stowing vehicle leveling jack. In that disclosure the structural components of the jack form the hydraulic cylinder itself, and the motor, pump, and hydraulic control circuit are all contained within the hydraulic ram assembly. Again, such a jack is overly complicated and is susceptible to damage in a gooseneck trailer application.
U.S. Pat. No. 4,112;,274, Sep. 12, 1978, to Vahrenkamp discloses a pneumatic jack assembly employed on the tongue of single-axle trailer. Such a pneumatic jack generally is not capable of generating the lifting forces necessary to raise and lower a fully loaded gooseneck trailer. Also, a pneumatic jack requires a heavy and cumbersome air compressor for operation. U.S. Pat. No. 3,431,727, Mar. 11, 1969 to Grumman discloses a jack arrangement for trailers including an electrically driven piston pump, which communicates with three leveling jacks to accomplish leveling of a house trailer. Again, such an arrangement is complicated and is not adapted for use with a gooseneck trailer.
A need exists, therefore, for a trailer with an improved lifting mechanism for connecting a gooseneck trailer to a truck bed that is protected from loading other than by the weight of the trailer and is protected from damage by impact from the bumper or other portion of the towing vehicle during coupling operations. Furthermore, a need exists for an improved lifting mechanism with a remote control to permit an operator to control the lifting mechanism while viewing its operation from a safe distance from the truck, trailer, and lifting mechanism.